Digital arrow location computer

ABSTRACT

A projectile path coordinate computing system for use with a detecting system wherein a projectile path is scanned by a beam of energy. The computer includes a binary counter and a clock for stepping the counter. Gating is provided to allow the clock to initiate the stepping of the counter at the initiation of the scan of the projectile path and means are provided for stopping the counter when the beam of energy is interrupted during its scan by a projectile so that the count in the binary counter when stopped is indicative of one coordinate of the position of the projectile within the scanned path. Means are also provided for translating the count into an indication of the coordinate of the projectile within the path.

United States Patent [72] lnventor Patrick J. Murphy Muskegon. Mich. 1211 Appl. No. 799,451 [22] Filed Feb. 14. 1969 [45] Patented June 29, 1971 I 73] Assignee Brunswick Corporation [54] DIGITAL ARROW LOCATION COMPUTER 13 Claims, 9 Drawing Figs.

[52] [1.8. CI 235/92 GA, 235/92 V, 235/92 R, 273/1022 R [51] Int. Cl 606m 1/272 [50] Field oISearch 235/92; 273/102.2; 235/193 [56] References Cited UNITED STATES PATENTS 3,475,029 10/1969 Hyman 273/1022 3,487,226 12/1969 Yettermmum 3,372,266 3/1968 Chilton r 1 4 v r r ABSTRACT: A projectile path coordinate computing system for use with a detecting system wherein a projectile path is scanned by a beam ofenergy. The computer includes a binary counter and a clock for stepping the counter. Gating is provided to allow the clock to initiate the stepping of the counter at the initiation of the scan of the projectile path and means are provided for stopping the counter when the beam ol'energy is interrupted during its scan by a projectile so that the count in the binary counter when stopped is indicative of one coordinate of the position of the projectile within the scanned path. Means are also provided for translating the count into an indication of the coordinate ofthe projectile within the path.

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ATENIEU JUNZQISTI SHEET 6 OF 6 MOTOR six/5T2? COORDINATE BULL'S EYE w LIP COMPUTOR CLUTCH l GEAR mi 0 A mam R o/sc c0050 use GEAR BRAKE 8 TRAIN .SL/P cu/rcu COORDINATE 360 Moron Conn/m DIGITAL ARROW LOCATION COMPUTER BACKGROUND OF THE INVENTION In the recent past, efforts have been directed toward provision of automated archery lanes, particularly for indoor use, involving a target remote from a firing line constructed in a way such that arrows do not remain impaled in the target but fall free for collection to be returned automatically to the archer at the firing line. In preferred systems, the target is constructed to be penetrable so that neither the target nor the arrow is substantially damaged by target penetration. Behind the target there is a suitable backstop which is usually yieldable in a way to absorb the energy of the arrow so that the latter stops and falls downwardly to an appropriate means for direct ing the arrow to a return conveyor. The return conveyor has preferably been in the form of a conveyor belt means which delivers the arrows to a container adjacent the firing line and accessible to the archer so that he merely has to remove an arrow from the storage container, fire at the target and await return of the arrow to the storage container. The return may be accomplished in a matter of a few seconds so that the archer may effectively practice his sport with only one or two arrows, if desired. Because the arrows do not remain impaled in a target for inspection by the archer, it has been contemplated in such systems that there would be a sensing apparatus for determining the location of the arrow hit in the target and controlling an indication means adjacent the firing line for showing the archer where the arrow struck the target.

SUMMARY OF THE INVENTION The invention relates to a computing system for computing the point of passage of a projectile along a path and in the exemplary embodiment. the same is adapted to be used with a projectile detecting means which scans the path in which the projectile passes. The system includes a computer comprised of a binary counter and a clock for stepping the binary counter. Gating is provided so that when the detecting system initiates the scan of the path, a synchronizing pulse is provided to permit the clock to begin to step the counter. Gating is also provided for stopping the counter when the detecting system ascertains that a missile has been found in the path so that the count on the counter is indicative of the position on the path along one coordinate of theprojectile. Means are also provided which halt the counter at a zero count level when no missile in the path has been detected so that the counter will await the next synchronizing pulse from the detecting system.

Normally, two such systems will be used so that two coordinates of the projectile within a path may be ascertained. In such a case, two indicating means having a common point indicator are driven by a motor responsive to a logic system receiving command position information from both of the binary counters. A binary coded disc feeds back position information of each indicator and movement of both indicators is stopped when the actual position information provided by the binary code disc matches the count in the binary counter.

Additional features include interlocking of the two computing systems so that spurious signals such as electrical noise received by one computation system will not cause the feeding of erroneous information to the associated indicator. Additionally, the system includes a separate indicator for indicating when a so-called "bull's-eye" has been obtained.

Further features include a projectile counter which provides an indication of the number of projectiles fired at a target and means whereby the point indicator is disabled during movement of the indicating means with which it is associated so that indications during the transition of the indication from one point to a subsequent point will not be present.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an archery installation, looking down a pair of lanes toward a pair of targets from a position adjacent an arrow quiver;

FIG. 2 is a perspective view partly broken away, illustrating a housing for the targets, backstops and arrow collectors for delivering arrows to a return conveyor;

FIG. 3 is a perspective view of the targets and scanning system looking from the rear of the housing with parts broken away;

FIG. 4 is a plan view ofthe scanning system,

FIG. 5 is a fragmentary vertical section of a housing for a light source, rotary mirrors, inclined mirrors and photocells;

FIG. 6 is a fragmentary vertical section of the housing for the mirrors and light source and photocells.

FIG. 7 is a logic diagram with certain elements shown in schematic form of the computing circuit for ascertaining one coordinate of the position ofa projectile within a path;

FIG. 8 is a plan view of a binary coded disc which provides actual indicator position information for feedback purposes; and

FIG. 9 is a block diagram illustrating the manner in which an indicating system is operated by two of the computers illustrated in FIG. '7.

DETAILED DESCRIPTION Referring now particularly to FIGS. 1 and 2, there is illustrated a substantially complete installation for two automated archery lanes side by side in which the entire apparatus is disassemblable and/or portable to permit removal from the floor surface utilized in order to leave it free for use for other purposes. As shown, the installation includes an arrow storage quiver 10 adjacent the firing line II adapted to serve two adjacent lanes 12 and 13 in that it is constructed to hold arrows as at IS in upright positions, either point up or fletching up, conveniently disposed for easy access by archers on both lanes. Targets for both lanes are provided in housing 18 located remotely from the firing line 11 and supported on wheels which facilitate adjustment of the housing toward and away from the firing line to permit adjustment in the length of the range.

In order to provide a target on each lane, the wall of the housing 18 facing the firing line is formed with a pair of large rectangular openings as at 19 and 20 and each aperture is closed by a penetrable screen 22 adapted to carry a target pattern as at 24 and constructed in a manner to permit arrows to pass through the screen without substantial damage to the screen or to the arrows. In a preferred form, the penetrable screen 22 comprises a plurality of vertically disposed closely adjacent flexible strands anchored at the top and bottom to the housing 18. For example, the strands may be 56 inch natural rubber or vinyl strands which provide both a suitable surface for the target and also long life with repeated arrow penetration. The target 24 may be painted on the screen 22 or may be an image projected onto the screen. The latter form has the advantage that the form of the target may be readily changed as desired.

At the rear of the housing 18, behind the target screens 22 there are suitable backstop means as at 28. As illustrated, each of the backstop means 28 is in the form of a free hanging net disposed in front of a fixed net in a manner such that the energy of the arrows fired through the target screens is absorbed by the backstop means in a manner to stop the arrow without damage to the arrow or the backstop, as a result of which the arrow falls downwardly for return toward the firing line. Other backstop means may be utilized and one acceptable form includes the use ofa free hanging bed of many strands of flexible material such as plastic tubing in sufficient numbers to provide a relatively thick barrier to the passage of arrows and yet have sufficient flexibility to absorb the energy of the arrows without rebound of the arrows.

The sidewalls and the top of the housing 18 may be suitably covered with appropriate material as at 29.

From the backstop means 28, the arrows fall downwardly toward suitable means for directing arrows from both lanes toward a central common return conveyor. As illustrated, the arrow gathering or collecting means in each lane comprises an endless conveyor as at 30 having a width substantially equal to the distance between the screen 22 and the backstop 28 and disposed to travel from the outer edge of the housing toward the center of the housing as represented by indicating arrow 32. The cross conveyor belts 30 are each arranged to pass about a pair of long support and drive rollers as at 34 and 35 on housing 18 at least one of which is arranged to be rotated by suitable drive means as at 36. Arrows fall from the backstop means 28 to the cross conveyors 30 as illustrated at 38, for example. While the arrows shown are disposed with the pointed ends leading for return to the firing line, some of the arrows fall from the backstop with the fletched end disposed toward the firing line, and the arrow return system is adapted to handle either arrangement easily. In practice, substantially more arrows return point first than fletching first.

The cross conveyors 30 deliver fallen arrows to a centrally disposed common arrow return conveyor 40 including an endless conveyor belt 41 supported adjacent the firing line on an idler roller associated with the quiver l0, and adjacent the housing 18 by a drive pulley on a motor 43. Intermediate the idler roller and the drive pulley, the long upper and lower reaches of the arrow return conveyor are supported by a channel structure 45. The arrangement is such that the conveyor belt 41 is driven at a relatively rapid rate so that arrows are returned in a matter of a few seconds and are thrown into the quiver with sufficient force to reach the storage positions 15.

In order to detect the position of an arrow relative to the target 24 as the arrow passes through the penetrable screen 22, there is an arrow detection system in the housing 18 including a housing 48 located centrally between the apertures 19 and and including a light and optical scanning system for sweeping two beams of light across each target area to provide two angular measurements in the forms of angular coordinates for indicating the position of the arrow. For example, as seen in FIG. 2, one beam of light is swept across the righthand target area from an effective starting position represented by line 49 to an effective finish position represented by line 50. Each light beam is directed toward a reflective strip on housing post 51. Preferably the detection system is used for purposes of controlling and indicating means associated with the quiver 10 and including an indica tor face for each lane as at 52 and 53 hearing an image as at 54 simulating the target 24. In a preferred form the indicator includes an indicator light movable about the indicating face and controlled by the arrow detection system.

The scanning system can best be understood with reference to FIGS. 3-6. As viewed in FIG. 3, the scanning unit, generally designated 100, is interposed between the targets 24 of the adjacent lanes 12 and 13. As will be seen hereinafter, the scanning unit 100 includes an upper scanner 102 and a lower scanner 104 and both scanners are operative to scan both ofthe lanes 12 and 13.

On the outboard side of the lane 13 and opposite from the scanning unit 100, there is located a pair of vertically oriented retroreflective tapes 106 and at the upper extremity of each of the tapes 106 there is located a start photocell 108.

Similarly, at the outboard side of the lane 12 and opposite the scanning unit 100, a pair of similar tapes 106 are located and at the lower extremity of each tape 106 there is provided a start photocell 108.

The retroreflective tapes 106 for each of the lanes 12 and 13 are horizontally spaced and the lower scanner 104 is adapted to project a rotating beam of light at the rearmost tape 106 associated with the lane 13 as well as the forward most tape 106 associated with the lane 12. The upper scanner 102 is adapted to project a rotating beam of light at the for vvardmost tape 106 associated with the lane 13 and the rearmost tape 106 associated with the lane 12. Stated another direction opposite from the direction in which the plane containing the beam oflight from the lower scanner 104 is askew.

The foregoing relation is illustrated in FIG. 4 wherein the beam of light generated by the upper scanner 102 is designated while the beam of light generated by the lower scanner 104 is designated 112.

The retroreflective tapes 106 are commercially known as 3M Brand photoelectric scanning tape sold by Minnesota Mining and Manufacturing Company and have the property of returning the light directly to its origin regardless of the striking angle. As a result, when a beam of light strikes the retroreflective tape 106, the beam of light will be reflected back towards its source without regard to the angle that the beam of light initially impinged upon the tape. The retroreflective tapes 106 are also of a sufficient length so that a moving beam of light from the upper scanner 102 will be able to completely sweep across the targets 24 and be returned to the upper scanner 102 provided that the beam has not been broken by a projectile such as an arrow. Similarly, the retroreflective tapes 106 associated with the lower scanner 104 have a length to provide the same capability with respect to the beam of light provided by the lower scanner 104. With reference to FIG. 3, the beams of light from the scanners 102 and 104 rotate in a counterclockwise direction.

Turning now to FIGS. 5 and 6, the construction of the scanning unit 100 may be seen. A vertically elongated housing is provided and within the same at about the vertical midpoint thereof, there is mounted a double ended laser 122 of conventional construction. Also located within the housing 120 is a power source 124 for the laser 122.

The double ended laser 122 may be of the type obtainable from Optics Technology, Inc. of Palo Alto, California and has the ability to provide two coaxial light beams, one from each end, of very narrow size. One such light beam is utilized by the upper scanner 102 while the other light beam is utilized by the lower scanner 104.

The use of the double ended laser 122 allows the scanning of two areas with but a single energy source. Furthermore, the laser is capable of producing light beam having a diameter significantly smaller than that of an arrow and with a high energy level so as to maximize system activity.

The manner in which the light beam from the laser 122 is utilized will now be described in conjunction with the lower scanner 104 with the understanding that the construction of the upper scanner 102 is identical. A mounting plate 126 within the housing 120 supports, near its lower end, a highspeed synchronous motor 128 having a rotary output shaft 130 to which a mirror 132 is affixed. The mirror 132 is externally silvered on both of its sides and, when driven by the motor 128, will rotate to deflect the beam of light from the laser 122 in a sweeping path just behind the target 24 (FIGS) 3 and 4) to the retroreflective tapes 106 with which it is as sociated on both of the lanes 12 and 13. In the exemplary embodiment, the synchronous motor 128 operates at 3,600 rpm. and the silvering of both sides of the mirror results in a scan rate of 7,200 scans per minute.

The laser 122 is located directly above the mirror 132 and arranged so that the beam of light emanating from one end thereof is focused on the mirror to point intersect the axis of rotation thereof. lnterposed between the laser 122 and the mirror 132 is an inclined, totally silvered mirror 134 having an aperture 136 therein through which the beam oflight from the laser 122 may pass to the mirror 132. The mirror 134 is located at an angle so that a beam oflight reflected by the mirror 132 towards the mirror 134 and not passing through the aperture 136 will be directed toward a lens 138 mounted on the plate 126 which then focuses the reflected beam of light on a stop photocell 140.

Finally, the housing 102 is provided with windows 142 adjacent to the mirror 132 through which the laser beam may be reflected by the mirror 132 externally of the housing to the tape [06.

From the foregoing description, it will be appreciated that normally the photocell 140 will be illuminated whenever the beam oflight 112 provided by the lower scanner 104 is sweeping across the confines of the target 24. This is due to the fact that as the mirror 132 rotates to sweep the beam oflight 112, and the latter impinges upon the retroreflective tape 106, the light beam will then be reflected back to the mirror 132 and, in turn, to the mirror 134 to be focused by the lens 138 on the photocell 140. The only time during the scan of the target 14 that the photocell 140 will not be illuminated is when the beam of light H2 is broken. This will occur when a projectile is within the scanned area and breaks the beam of light 112. Accordingly, the photocell 140 provides an indication of the time when the beam oflight is broken by a projectile.

In order to insure that the beam of light is broken by a projectile, it is necessary that the angular velocity of the sweeping beam of light be such that it will completely scan the target area 14 before projectiles can pass through the plane in which the light beam rotates. When, as is the case with the exemplary embodiment, the scanning system is intended for use in detecting arrows, the above-mentioned scan rate is sufficient to detect even the shortest arrows now used, even if shot at the target at the highest velocity obtainable with current bows. Projectiles having a shorter length than arrows and/or fired at the target at higher velocity than a high velocity arrow, are capable of detection using the principles of the invention. For such shorter projectiles and/or higher velocity projectiles, it will, of course, be necessary to increase the scan rate and it may also be desirable to use extremely high quality photocells that are extremely sensitive to rapid changes in illumination as when the beam oflight is broken by the projectile.

Returning to FIG. 3, it will be observed that the location of the start photocell 108 is such that for the direction of rotation of each light beam 112 or 110, the photocell 108 will be briefly illuminated at the beginning of each sweep of the beam of light across the target. As a result, the photocells 108 provide a signal indicating when in time a scanning cycle has been initiated. Because synchronous motors l28 are used to drive the beam of light through its scan, the rate of the scan is constant. It can be determined when the scan was initiated and when in the scan the beam was interrupted by interrogating the photocells I08 and 140 and thus, the angular position of the beam of light at the time it was interrupted can be determined to thereby provide information relative to one coordinate of the point of impact of the projectile on the target 24.

As mentioned previously, the upper scanner X02 works in an identical manner but provides information relative to a second coordinate of the point of impact. By means ofa com' puter that utilizes information from the photocells 108 and 140 for both the upper and lower scanners 102 and 104 on one lane, two coordinates of the point of impact of a projectile are determined, and thus, the exact point of impact can be determined.

A computer circuit for use in the archery range is seen in FIG. 7 which illustrates, in logic form, the circuitry required to ascertain one coordinate of the passage of the arrow through the target. In the preferred embodiment, it is to be understood that four such circuits are employed to provide two coordinates on each of two different ranges. It should be further understood that all gates illustrated are NAND gates which perform various AND and OR functions, and that the characterization of a gate as, for example, as an AND gate refers to its function as opposed to its structure.

The computer includes a conventional clock 300 which acts as a source of timed electrical pulses as an input to an AND gate 302. The output of AND gate 302 is connected to the trigger input in the first stage of a binary up counter. The binary up counter includes seven stages designated BC-l, BC-Z, BC-4, BC-8, BC-l6, BC-32 and B064, with a number follow ing the letters representing the count held in each particular stage. Thus, the maximum count ofthe counter is 127.

When the AND gate 302 is enabled, pulses from the clock 300 will cause the counter to step. However, when the AND gate 302 is disabled, the count in the counter will remain the same.

A line to the AND gate 302 is taken from the output of a stop-start flip-flop 304 which is set to initiate the count coincidentally with the beginning of the scan ofthe associated light beam. More specifically, an input to the set section of the flipflop 304 is taken from the output of an AND gate 306 which in turn has one input taken from an amplifier 308 through an inverter 309. The amplifier 308 is connected to the photocell 108 which is illuminated at the beginning of the scan by the rotating beam of light. Thus, when the photocell 108 is illuminated, the amplifier 308 generates a synchronizing pulse which under certain conditions is passed by the AND gate 306 to set the flip-flop 304 thereby causing the count to be in itiated.

The AND gate 302 may also be disabled to preclude the counter from counting. Specifically, the AND gate 302 is disabled whenever the flip-flop 304 is in a reset condition and such an occurrence will take place when the photocell 140 has its light beam interrupted by an arrow passing through the target. The temporary lack of illumination of the photocell 140 causes a change in signal which is magnified by an amplifier 310 and passed as an input to the reset section of the flip-flop 304. Thus, whenever an arrow passes through the target, the counting of the counter will cease.

It will be recognized that, in view of the speed of the scan of the light beam, significantly more often than not, the light beam will pass through a cycle without being interrupted by an arrow. In such a case, it is desired to stop the counter at binary zero and this is accomplished by resetting the flip-flop 304 to inhibit the AND gate 302. To this end, an output from an AND gate 316 is fed as an input to the reset section of the flipflop 304. The AND gate 316 includes inputs taken from each of the seven flip-flops BC-l through 8064 comprising the counter. Thus, when each of the flip-flops BC-l through BC- 64 is in a reset condition, corresponding to a zero count therein, the AND gate 316 will issue a signal which is passed on to the flip-flop 304 to reset the same thereby stopping the counting process until the flip-flop 304 is again set when the photocell 108 is illuminated at the beginning ofa scan.

The period of the clock 300 and the capacity of the counter are chosen so that the counter will reach its capacity at about the time the beam of light associated therewith from the scanner terminates its sweep across the target area.

in view of the foregoing, it will be appreciated that the count on the counter when stopped at any position other than zero count, will be representative of the position of the as sociated light beam within its scanning path in view of the fact that the counter is started when the scan is initiated and is stopped when an arrow is detected. As a result, the count on the counter can be used to provide information for controlling a portion of an indicator and the condition of the counter is read when necessary to provide such control information.

As mentioned previously, when the count in the counter is zero, the AND gate 316 causes the resetting of the flip-flop 304. However, at all other times, the output signal of the AND gate 316 is at the opposite level and may be used when other conditions are present to cause a reading of the counter. To this end, a line from the output of the AND gate 316 is used as an input to an AND gate 318 together with a second input from the output of the reset section of the flip-flop 304. The arrangement is such that when the flip-flop 304 is reset and the count contained in the counter is not zero, the AND gate 318 will issue a signal to set a flip-fiop 320 which issues a READ signal from an output from its set section.

An output of the flip-flop 320 is also utilized as an input to the AND gate 306 to inhibit the same whenever the counter is to be read. This provision is made in order that the counting procedure cannot be improperly initiated by the beam of light hitting the photocell 108 at the beginning of a scanning sequence when the previous scanning cycle had resulted in the detection of an arrow passing through the target and the indicator has not yet fully responded. Thus, for the period of time that the flip-flop 320 is set to cause the reading of the counter, AND gate 306 is inhibited to thereby preclude the passing of any pulses from the clock 300 to the counter.

The same output of the flip-flop 320 is also used as in input to an OR gate 324 which has its output connected through a diode to the emitter of a unijunction transistor within a unijunction transistor circuit 322. When the flip-fiop 320 is reset, the emitter of the unijunction transistor is clamped at a level to preclude the charging of a capacitor 325 from charging. However, when the flip-flop 320 is set corresponding to a READ condition, the emitter of the unijunction transistor within the circuit 322 is then placed at a level whereby a capacitor 325 therein may begin to charge so that after a predetermined period, the unijunction transistor may fire to reset the flip-flop 320. Normally, the RC combination in the circuit 322 should be chosen so that about seconds may elapse before the unijunction transistor therein is fired to reset the flip-flop 320 through the circuit just described. However, as will be seen hereinafter, provision is made for causing resetting of the flip-flop 320 in a more rapid manner.

The OR gate 324 includes a second input which is similarily connected to a corresponding flip-flop 320 in the computer circuit for the second coordinate of projectile path. Thus, when either one of the two flip-flops 320 is in a set condition, the unijunction timing circuit 322 will be energized.

Another output of the flip-flop 320 also serves as an input to two AND gates 326 and 328 which are used to control the direction of movement of an indicator for one coordinate as will be seen in greater detail hereinafter.

The computer further includes a directional control flipflop 330 which provides signals to the AND gates 326 and 328 for the purpose of determining the direction of movement of the indicator, The flip-flop 330 includes an input to its set sec-- tion from the output of the AND gate 306 which causes the flip-flop 330 to be placed in a set condition at the beginning of each scanning cycle. As will become apparent hereinafter, when the flip-flop 330 is in a set condition, counterclockwise rotation of an indicator drive motor is called for while when the flip-flop 330 is in a reset condition, clockwise rotation of the indicator drive motor is called for.

An output from the set section of the flip-flop 330 is taken as an input to the AND gate 326 while an output from the reset section of the flip-flop 330 is taken as an input to the AND gate 328.

A third input to both of the AND gates 326 and 328 is taken from the output of an AND gate 334 which receives its inputs from a conventional comparator circuit, generally designated 336.

The comparator circuit 336 includes 21 inputs (only three of which are shown) with seven of the inputs being taken from the outputs of the reset sections of the flip-fiops BC-I through BC-64 comprising the counter and seven being taken from the set sections of the flip-flops BC-1 through BC-64. The other seven inputs to the comparator 336 are taken from a binary coded position disc shown schematically at 338.

The coded disc is mounted for rotation and mechanically linked to the indicator so that its position is changed with a change of the indicator position.

The coded disc 338 is illustrated in FIG. 8 and is seen to comprise a circular disc having on one surface thereof seven rows of conductive segments 339. Beginning outwardly and progressing radially inward, the rows are designated CD-l, CD'Z, CD-4, CD-8, (SD-l6, CD32 and CD64 and, as is the case with the reference numerals relating to the counter, the numerals associated with each of the rows CD-l -CD-64 cor respond to the binary number which the segment represents. In use, a plurality of brushes 340 are provided, one for each of the conductive rows CD-XCD64 and provide input signals to the comparator 336 whenever the brush 340 associated with a particular row is on one of the conductive portions.

Also provided on the coded disc 338 are a pair of segments 34! which are adapted to be contacted by brushes 342 (FIG. 1] when the coded disc has reached the limit of its rotation in either direction to provide energization signals to the AND gates 326 and 328 to reverse the motor for the indicator. It is to be noted that as illustrated in FIG. 8 the conductive segments are provided about approximately 320 of the disc 338 As will be seen hereinafter, arms associated with the indicator are adapted to be moved about an axis approximately and thus, the mechanical arrangement of the coded disc 338 with respect to such indicator arms should be that the disc 338 be geared to the indicator arms at a 4:1 ratio.

Those skilled in the art will recognize the comparator circuit 336 is such that when the count picked off of the coded disc 338 is the same as that contained in the counter, the AND gate 334 will issue a signal indicative of the match in the counts. However, whenever the comparator determines that no match is present, the output levels of the AND gate 334 will be such as to provide an enabling input to gates 326 and 328.

The fourth and final input to each of the AND gates 326 and 328 is received on a line 337 which is taken from the computer which determines the other coordinate of the point of impact of the projectile upon the target. Specifically, the line 337 is connected to the output of the set section of the corresponding flip-fiop 320.

As a result of the foregoing, it will be appreciated that the AND gates 326 and 328 can never be enabled simultaneously and the particular one of the AND gates 326 and 328 that is enabled depends upon the condition of the flip-flop 330 assuming that all other appropriate inputs are present. As a result, the AND gate 326 is enabled when the flip-flop 320 is set corresponding to a READ condition, the flip-flop 330 is set to indicate counterclockwise drive, the output of the AND gate 334 indicates that no match has been obtained and when the corresponding flip-flop 320 is in the associated computer circuit is also set,

The conditions for enabling of the AND gate 328 are identical to that for the AND gate 326 except that flip-flops 330 must be in a reset condition rather than in a set condition.

As mentioned previously, the flip-flop 330 will normally be in a set condition from the initiation of each scan cycle until such time as the AND gate 334 determines that a match exists between the count picked off of the coded disc 338 matches the count contained in the binary counter; and that thereafter, the flip-flop 330 will be in a reset condition. The setting of the flip-flop 330 occurs when the AND gate 306 sets the flip-flop 304 in the manner mentioned previously and the resetting of the flip-flop 330 occurs when the AND gate 334 issues a signal indicative of a match which is inverted by an inverter 343 and fed through an AND gate 344 to the reset section of the flip flop 330. The AND gate 344 is normally enabled but will be disabled whenever the flip-flop 320 is in a set condition requiring the reading ofthe counter for indication purposes.

The purpose of the foregoing is due to the geometry of the indicator and will be apparent from the followin Normally, the disc 338 will be in a position dictated by the indications of the previous shot and will be continuously applying a signal in" dicating a particular position count to the comparator 5 The indicator construction is such that for a lesser count in the counter than that being picked off of the disc 338 the motor for driving the indicator should be driven in counterclockwise direction. As a result, from the time the counter begins to count and before it reaches the point where the count contained therein is equal to the count being picked off of the disc 338, the flip-flop 330 will provide an enabling input to the AND gate 326 and a disabling input to the AND gate 328. Similarly, the count contained in the counter exceeds that being picked off of the disc 338, the geometry of the indicator is such that clockwise rotation of the drive motor is required. As a result, when the point is reached where the count contained in the counter corresponds to the count being picked offof the disc 338, the AND gate 334, sensing the match, will cause the AND gate 344 to reset the flip-flop 330 so that as the count contained in the counter increases above that being picked off of the disc 338, the AND gate 328 will receive an enabling signal while the AND gate 326 will receive a disabling signal.

As mentioned previously, the input to the AND gate 344 from the flip-flop 320 is used merely as an inhibiting input. Thus, whenever it is desired to read the counter to cause the indicator to respond thereto, the AND gate 344 is inhibited to preclude the flip-flop 330 from being reset when a match is obtained assuming that it has not already been reset. Stated another way, during the reading of the counter for moving the indicator, the condition of the flip-flop 330 cannot be changed.

The motor for driving the indicator is designated 350 and is a direct current motor so that its direction of rotation depends on the direction ofcurrent flow therethrough.

As indicated schematically. the motor 350 drives the coded disc 338 and also drives an indicator arm. As a result, the position of the decoder disc 338 and the count picked off of the same is indicative of the position of the indicator arm associated therewith. Specific details of arrangement will be described hereinafter.

The indication of the point of passage of an arrow or other missile through the target is indicated on a target monitor by a movable display lamp shown schematically at 356 and which is connected to control circuitry by brushes 357 engaging linear commutator segments 358. By means to be described in greater detail hereinafter, the position of the display lamp 356 is altered with respect to the transluscent target face identical to the target at which the projectile is aimed and the arrangement is such that the lamp 356 is illuminated after the com puter circuitry has responded to the information provided thereto by the sensing system. Thereafter, the position of the lamp is held until the next arrow or projectile passes through the target and during this period, the lamp 356 is illuminated. However, whenever the position of the lamp 356 is being changed, it is extinguished.

This is accomplished by connecting one of the commutator segments 358 directly to a source of power and the other to an electronic switch 359 which is driven by an inverter 360. The inverter 360, in turn, receives its input from the output of an AND gate 361 which receives a first input from a line includ ing an AND gate 362 which has one input taken from the output of the AND gate 326 and another input taken from the output of the AND gate 328. The arrangement is such that when both AND gates 326 and 328 are disabled, the AND gate 362 will ultimately cause the application of one enabling input to the AND gate 361.

A second input to the AND gate 361 is taken from a line including an AND gate 362 (not shown) in the computer circuit for determining the other coordinate. As a result, it will be ap preciated that AND gate 361 will be enabled only when both of the two indicator drive motors are deenergized, which will be the vast majority of the time, so that the electronic switch 359 will not illuminate the display lamp 356 during indicator movement.

An output from the and gate 36] is also fed through an in verter 363 to the emitter of the unijunction transistor within the unijunction transistor circuit 322. The circuit arrangement is such that when the AND gate 36] becomes enabled to illuminate the lamp 356, the unijunction transistor circuit 322 will time out much more rapidly than the same would be virtue of its connection to the gate 324 to thereby cause virtually immediate resetting of the flip-flop 320 to eliminate the READ signal provided thereby to ready the circuit for the next suc ceeding arrow.

A further advantage of the just described circuitry is to preclude spurious signals received by but a single computer circuit from causing the flip-flops 320 from being set over a prolonged period. For example, when but a single computer system is triggered as by electrical noise, it will be appreciated that notwithstanding the setting of the flip-flops 320 due to the spurious noise signals, both of the AND gates 326 and 328 will remain disabled as a READ signal from but a single one of the flip-flops 320 will be received. Thus, AND gate 361 will continue to remain in an enabled condition and the output signal thereof will be continuously applied by the inverter 363 to the unijunction timing circuit 322 in the same manner as when the AND gate 361 switches from a disabled condition during indicator movement to an enabled condition when such movement is concluded. Thus. a rapid reset of the spuriously set flip-flop 320 will occur.

An output from the line including the AND gate 362 is also used to control an electromagnet brake 364 which, as will be described in greater detail hereinafter, will immediately stop movement of the drive of the indicator arm. Electromagnetic brake 364 is energized through a circuit including a driver 365. The arrangement is such that whenever no energization of the motor 350 is called for by the output of either of the AND gates 326 and 328, the electromagnetic brake 364 will be energized.

The system additionally includes a projectile counter, generally designated 366 which is comprised ofa conventional 3-bit binary coded up counter including flip-flops AC4, A02 and AC-4. To step the counter 366, a line to the trigger input of the flip-flop AC-l is taken through a pulse generator 368 connected to the output of the AND gate 361. As a result, whenever the AND gate 361 goes from a disabled to an enabled condition, the pulse generator 368 will apply a pulse to the counter 366 thereby increasing the count contained in there by one.

Also provided in the projectile counter is a conventional binary decimal decoding matrix 370, which, in the exemplary embodiment, is capable of decoding a count up to decimal six. Counts from one to five are used to illuminate five lamps L- lL-5 with the arrangement being such that the particular lamp L-l-L-S that is illuminated indicates the number of projectile that have been sensed and indicated.

When the counter 366 is stepped to a condition corresponding to decimal six, an output from the decoding matrix 370 is fed back to each of the flip-flops AC-l-AC-4 to automatically reset the same. Such a condition will occur when flip-flop AC-] is reset and both ofthe flip-flops AC-2 and AC-4 are set.

Provision is also made for manually resetting the counter 366 and to this end, a normally open switch 372 is also connected to the flip-flops AC- lAC-4 such that when a shooter manually closes the switch 372, the counter 366 will be reset to a zero condition.

While the exemplary embodiment provides counting system having a capacity of five, it will be appreciated that using the principles disclosed herein, a greater or a lesser number of projectiles could be counted and indicated.

Another feature of the system is to provide a separate indication when a bull's-eye is achieved. it will be recalled that the lamp 356 illuminating the point of impact of the projectile on the target on a target monitor is movable and advantage is taken of this fact to provide an indication when the lamp 356 is positioned at the bull's-eye region. As shown schematically in FIG. 7, there is provided a brush 380 movable with the lamp 356 and a contact 382 which is located so as to be contacted by the brush 380 whenever the lamp 356 is positioned at the bull's-eye region. The brush 380 is electrically connected to the output of the electronic switch 359 so that whenever the same has an output causing lamp 356 to be illuminated, and when the brush 380 is on the contact 382, a signal will be applied as an input to a one shot 386 causing the same to change its condition.

The one shot 386 is constructed to have a relatively long stay in its unstable state. In the exemplary embodiment, the time period may be on the order of2 seconds.

An output from the one shot 386 is, in turn, connected to a lamp 388 which will be illuminated whenever the one shot is in its unstable condition. Thus, when a bulls-eye has been detected and the brush 380 contacts to the contact 382 to cause the one shot 386 to change to its unstable state, the lamp 388 will be energized to indicate that a bulls-eye has been obtained and will remain energized for 4 seconds, at which time, the one shot 386 will automatically revert to its stable state.

An output from the oneshot 386 may also be used to energize a relay 390 having normally open contacts 390a in series with a bell 392 across a source of power. Thus, when the one shot 386 switches to its unstable state, the relay 390 will be energized for 4 seconds to close the contacts 390a and ring the bell 392.

if desired, and when more than one range is used, the bell 392 and associated circuitry may be common to two adjacent ranges. To this end. the relay 390 may be energized by another one shot 386 for the computer circuitry of the adjacent lane (not shown). in this case, each input to the relay 390 should be provided with isolation diodes 394 to insure that the obtaining ofa bull's-eye on one range, while causing the bell 392 to be rung, will not cause the bull's-eye lamp 388 for the ad jacent lane to be illuminated.

Turning now to FIG 9, the mariner in which the computer circuitry described previously operates an indicator is illustrated in schematic form. With the exception of the drive means and provision of the bull's-eye light brush and contact, the indicator takes the same form as that disclosed in US. Pat. No. 3,40l ,937 to Rockwood et al. and assigned to the same as signee as the instant application; and reference thereto is made for the purpose of incorporating the details thereof herein by reference. For purposes of the instant invention, it is sufficient to observe that the indicator includes two movable arms 400 and 402 with the arm 402 carrying a movable carriage 404 which cammingly engages the arm 400. The arrangement is such that when the arms 400 and 402 are in dented, the carriage 404 will be located approximately below the point of impact ofa projectile on the target to indicate the same.

Target markings 406 are located on a translucent plate above the carriage 404 and the latter is provided with the lamp 356 to pinpoint the spot ofimpact on the target markings 406. The carriage 404 also includes the brush 380 and mounted below the brush 380 is a contact 382 to operate the bull's-eye light. More specifically, the contact 382 may be located below the bulls-eye of the target markings 406 so that when the lamp 356 is positioned under the center of the bulls-eye, the brush 380 will contact the contact 382 for purposes of ener gizing the bull'seye indicating circuit in a manner described previously.

Each of the arms 400 and 402 includes an identical drive circuit which is comprised of a motor 350 which drives a gear train 408 through a slip clutch 410. The drive train 408 in turn drives the respective one of the arms 400 and 402 about an axis 412. The gear train additionally rotates the coded disc 338 for its respective computer.

The brake 364 is operative upon an associated one of the gear trains 408 to stop the same when the conditions mentioned previously are present.

The manner of operation of the drive systems for each of the arms 400 and 402 is identical and may be described briefly as follows. When the computer energizes the motor 350 in the manner mentioned previously, the same will drive the associated gear train 408 through the slip clutch 410 thereby moving the associated one of the arms 400 or 402 and the associated coded disc 338. When the coded disc 338 reaches a position wherein the count picked off of the Same matches the count contained in the counter of the computer, the match signal determined by the associated computer stops the energization of the associated motor 350 and immediately energizes the associated brake 364. At this time, all movement of the gear train 408 is stopped and thus no further movement of the associated arm 400 or 402 will take place so that the carriage 404, and thus the indicator light 356, will be located at the correct position below the target markings 406 and the target monitor. The motor 350 may continue to coast to a stop and such continued coasting rotation of the motor 350 will not alter the position of the gear train which has been braked because ofthe presence of the slip clutch 410.

If the bull's-eye has been detected, it will be appreciated that the carriage 404, and thus the brush 380 will be positioned below the bulls-eye with the brush 380 making contact with the contacts 382 to energize the bulls-eye circuitry. Lamp 356 will be illuminated to indicate the position and the position of the arms 400 and 402 will remain in the dictated location until another read cycle takes place at which time, the lamp 356 will be extinguished in the manner described previously, the brakes 364 will be released and the motors 350 operated by their associated computers in the manner described previously to adjust the position of the arms 400 and 402 to indicate the point ofimpact ofthe subsequent arrow.

l claim:

1. A projectile path coordinate computer comprising; a counter having a predetermined capacity which when exceeded results in automatic resetting of the counter, means for stepping said counter at a predetermined rate, means for enabling said counter in response to the beginning of a scan of a target area, first means for disabling said counter when a projectile is encountered in said target area and whereby the accumulated count therein is a measure of the time in the scan when a projectile was encountered and thus a measure of the position of the projectile in the target area, and second means for disabling said counter when its predetermined capacity is exceeded so that said counter is held in a reset condition until said enabling means again enables said counter to thereby synchronize the stepping of the counter and the scan of the target area, said counter comprising a binary counter and said stepping means comprising a clock; movable indicator means; binary coded means associated with said indicator means for providing a count representative of the position of said indicator means; means for comparing the count in said counter and the count provided by said binary coded means; and means for operating said indicator means responsive to said comparing means when said first disabling means is operative.

2. A projectile coordinate computer according to claim 1, wherein said indicator means includes a bidirectional motor; means responsive to said enabling means for initially prepar ing said motor to drive in one direction; and means responsive to said comparing means for preparing said motor to drive in the other direction when said comparing means determines a match of the count in said counter with the count provided by said binary coded means.

3. A pair of projectile coordinate computers according to claim 1 for ascertaining two coordinates of a projectile path; and further including means responsive to the first disabling means of both said computers for precluding movement ofthe indicator means of both of said computers except when the first disabling means of both of said computers is operative.

4. A pair of projectile coordinate computers according to claim 3, further including projectile counting means; projectile count-indicating means responsive to said projectile counting means; and means responsive to the first disabling means of both of said computers for stepping said projectile counting means when both said first disabling means are operative.

5, A pair of projectile coordinate computers according to claim 3, wherein indicator means of both said computers include a common point indicator lamp; and means for extinguishing said lamp whenever one of said indicator means is moving.

6. A pair of projectile coordinate computers according to claim 3, wherein the indicator means of both said computers are adapted for cooperative movement relative to a target indicator having a "bulls-eye, and separate bulls-eye" indicating means operative in response to the movement of the indicator means of both said computers to a bull's-eye position on said target indicator.

7. A pair of projectile coordinate computers according to claim 3 wherein the indicator means of both said computers are adapted for cooperative movement relative to a target indicator and separate indicating means operative in response to the movement of the indicator means of both of said computers to a predetermined region on said target indicator for providing a separate indication thereof.

8. A pair of projectile coordinate computers according to claim 7 wherein said separate indicating means comprises a first electrical contact located in proximity to target indicator and at a predetermined position with respect to said predetermined region, a second electrical contact movable with both of said indicator means and positioned to make electrical contact with said first electrical contact when both of said indicator means are at said predetermined region, and signal means energizable in response to said second electrical contact electrically contacting said first electrical contact.

9. A projectile coordinate computing system comprising at detecting means for providing infonnation relative to two coordinates of the position of a projectile within a path, said detecting means including a pair of spaced scanners, one for each coordinate, for cyclically scanning said path and detecting projectiles therein, and two separate computing systems for receiving information relative to each coordinate respectively; each of said systems including a binary counter, clock means for driving the binary counter, gating means responsive to the beginning of the scan by the associated scanner for permitting the counter to be driven by the clock, means respon sive to the detection of the projectile in the path by the associated scanner for precluding the clock from driving the counter, and means for stopping the counter at binary zero until said gating means responds to the initiation of the subsequent scanning cycle.

l0. A projectile coordinate computing system and indicating means comprising: a computer including timing means; means for cyclically scanning a path in which a projectile may pass and for providing a signal indicative of the detection of the projectile in said path; means responsive to the initiation of the scanning of said path by said scanning means for initiating the operation of said timing means; means responsive to the detection of a projectile in said path by said scanning means for stopping said timing means whereby the condition of said timing means provides an indication ofa coordinate of the projectile within said path; movable indicating means, in-

cluding a bidirectional drive motor, responsive to said timing means for determining the condition of said timing means and indicating the same as a coordinate for the position of a projectile within said path; and switch means operated by said computer for conditioning said motor for movement in one direction during a first portion of a scan and for conditioning said motor for movement in the other direction during a second portion of a scan.

11. The projectile coordinate computing system of claim 10 wherein said indicating means includes a movable indicator and feedback means for providing information relative to the position of said indicator, comparing means for comparing the condition of said timing means and said information provided by said feedback means, and said switch means includes means responsive to said means for initiating operation of said timing means for normally conditioning said motor to move in one direction, and means responsive to said comparing means for conditioning said motor to operate in the other direction when said comparing means determines a match between the conditions of said timing means and said feedback means.

12. The projectile coordinate computing system of claim 11 wherein said motor means comprises a direct current rotary motor and said switch means includes a first switching device connected to a source of power and to one side of said motor, a second switching device connected to the other side of said motor and the other side of said source of power, means responsive to the operation of said first switching device for operating said second switching device; a third switching device connected to said one side of said source of power and to said other side of said motor, a fourth switching device connected to said one side of said motor and said other side of said source of power, and means responsive to the operation of said third switching device for operating said fourth switching device; and means for alternately operating one of said first and third switching devices.

13. The projectile coordinate computing system of claim 12 wherein all of said switching devices comprise transistors. 

1. A projectile path coordinate computer comprising; a counter having a predetermined capacity which when exceeded results in automatic resetting of the counter, means for stepping said counter at a predetermined rate, means for enabling said counter in response to the beginning of a scan of a target area, first means for disabling said counter when a projectile is encountered in said target area and whereby the accumulated count therein is a measure of the time in the scan when a projectile was encountered and thus a measure of the position of the projectile in the target area, and second means for disabling said counter when its predetermined capacity is exceeded so that said counter is held in a reset condition until said enabling means again enables said counter to thereby synchronize the stepping of the counter and the scan of the target area, said counter comprising a binary counter and said stepping means comprising a clock; movable indicator means; binary coded means associated with said indicator means for providing a count representative of the position of said indicator means; means for comparing the count in said counter and the count provided by said binary coded means; and means for operating said indicator means responsive to said comparing means when said first disabling means is operative.
 2. A projectile coordinate computer according to claim 1, wherein said indicator means includes a bidirectional motor; means responsive to said enabling means for initially preparing said motor to drive in one direction; and means responsive to said comparing means for preparing said motor to drive in the other direction when said comparing means determines a match of the count in said counter with the count provided by said binary coded means.
 3. A pair of projectile coordinate computers according to claim 1 for ascertaining two coordinates of a projectile path; and further including means responsive to the first disabling means of both said computers for precluding movement of the indicator means of both of said computers except when the first disabling means of both of said computers is operative.
 4. A pair of projectile coordinate computers according to claim 3, further including projectile counting means; projectile count-indicating means responsive to said projectile counting means; and means responsive to the first disabling means of both of said computers for stepping said projectile counting means when both said first disabling means are operative.
 5. A pair of projectile coordinate computers according to claim 3, wherein indicator means of both said computers include a common point indicator lamp; and means for extinguishing said lamp whenever one of said indicator means is moving.
 6. A pair of projectile coordinate computers according to claim 3, wherein the indicator means of both said computers are adapted for cooperative movement relative to a target indicator having a ''''bull''s-eye,'''' and separate ''''bull''s-eye'''' indicating means operative in response to the movement of the indicator means of both said computers to a bull''s-eye position on said target indicator.
 7. A pair of projectile coordinate computers according to claim 3 wherein the indicator means of both said computers are adapted for cooperative movement relative to a target indicator and separate indicatIng means operative in response to the movement of the indicator means of both of said computers to a predetermined region on said target indicator for providing a separate indication thereof.
 8. A pair of projectile coordinate computers according to claim 7 wherein said separate indicating means comprises a first electrical contact located in proximity to target indicator and at a predetermined position with respect to said predetermined region, a second electrical contact movable with both of said indicator means and positioned to make electrical contact with said first electrical contact when both of said indicator means are at said predetermined region, and signal means energizable in response to said second electrical contact electrically contacting said first electrical contact.
 9. A projectile coordinate computing system comprising a detecting means for providing information relative to two coordinates of the position of a projectile within a path, said detecting means including a pair of spaced scanners, one for each coordinate, for cyclically scanning said path and detecting projectiles therein, and two separate computing systems for receiving information relative to each coordinate respectively; each of said systems including a binary counter, clock means for driving the binary counter, gating means responsive to the beginning of the scan by the associated scanner for permitting the counter to be driven by the clock, means responsive to the detection of the projectile in the path by the associated scanner for precluding the clock from driving the counter, and means for stopping the counter at binary zero until said gating means responds to the initiation of the subsequent scanning cycle.
 10. A projectile coordinate computing system and indicating means comprising: a computer including timing means; means for cyclically scanning a path in which a projectile may pass and for providing a signal indicative of the detection of the projectile in said path; means responsive to the initiation of the scanning of said path by said scanning means for initiating the operation of said timing means; means responsive to the detection of a projectile in said path by said scanning means for stopping said timing means whereby the condition of said timing means provides an indication of a coordinate of the projectile within said path; movable indicating means, including a bidirectional drive motor, responsive to said timing means for determining the condition of said timing means and indicating the same as a coordinate for the position of a projectile within said path; and switch means operated by said computer for conditioning said motor for movement in one direction during a first portion of a scan and for conditioning said motor for movement in the other direction during a second portion of a scan.
 11. The projectile coordinate computing system of claim 10 wherein said indicating means includes a movable indicator and feedback means for providing information relative to the position of said indicator, comparing means for comparing the condition of said timing means and said information provided by said feedback means, and said switch means includes means responsive to said means for initiating operation of said timing means for normally conditioning said motor to move in one direction, and means responsive to said comparing means for conditioning said motor to operate in the other direction when said comparing means determines a match between the conditions of said timing means and said feedback means.
 12. The projectile coordinate computing system of claim 11 wherein said motor means comprises a direct current rotary motor and said switch means includes a first switching device connected to a source of power and to one side of said motor, a second switching device connected to the other side of said motor and the other side of said source of power, means responsive to the operation of said first switching device for operating said second switching devIce; a third switching device connected to said one side of said source of power and to said other side of said motor, a fourth switching device connected to said one side of said motor and said other side of said source of power, and means responsive to the operation of said third switching device for operating said fourth switching device; and means for alternately operating one of said first and third switching devices.
 13. The projectile coordinate computing system of claim 12 wherein all of said switching devices comprise transistors. 